Cardboard tube plug



FIG. 1 is an isometric view of the cardboard tube plug embodying thepresent ornamental design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a rear view thereof, showing the claimed cardboard tube plugin an upside down position;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in FIG. 7 represent the three dimensional configurationof the four innermost circular surfaces, and form no part of the claimeddesign.

CLAIM The design for a cardboard tube plug, as shown and described.